KUALA LUMPUR: A simple wave from a boy to a passing Keretapi Tanah Melayu Berhad (KTMB) train in Kempas, Johor, warmed hearts online after the driver returned the greeting with a wave and a honk.

The moment, captured on video and shared on Threads by the boy's mother, user @_zrily, showed her son waving at the passing train before the driver responded.

Delighted by the gesture, she took to social media to thank the driver for making her son's day.

"Who was the man driving the train near Kempas at 6.30pm earlier? Thank you so much for making my child so happy today," she wrote.